Ti/BMMs(Ti supported bimodal mesoporous silica) catalysts have been prepared via self-assembly route combined with ship-in-a-bottle method.The recovery and recycling performances of Ti/BMMs were investigated in the ep...Ti/BMMs(Ti supported bimodal mesoporous silica) catalysts have been prepared via self-assembly route combined with ship-in-a-bottle method.The recovery and recycling performances of Ti/BMMs were investigated in the epoxidation of cyclohexene.In order to the evaluate the regeneration methods and to examine the deactivation behaviors,the deactivated Ti/BMMs catalysts were washed in chloroform or calcinated at 450 °C for 6 h and then activity of the recovery catalysts were examined.Meanwhile,the structure features and surface properties of the regenerated catalysts were characterized by X-ray diffraction,N_2-sorption analysis,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,thermogravimetric analysis,UV visible spectroscopy and X-ray photoelectron spectroscopy.The results showed that the typical bimodal mesoporous structure of recycled Ti/BMMs catalysts was still maintained,and the phenomenon of Ti leaching during the catalytic process and recovery was negligible.In particular,spectroscopic observations indicated that the effects of the regeneration methods on the tetrahedrally-coordinated Ti species and catalytic deactivation were remarkable.The main reasons were related to the polarities of used solvents during recovery tests,the environment medium of adsorbed water inside mesopore channels and the deposition of bulky molecules of by-products on the mesoporous surface.展开更多
结合Ti、V、Nb元素对焊接热影响区微观组织的影响,添加不同微合金元素,进行实验室真空冶炼-轧制DH36高强船板钢。利用Gleeble3500试验机,针对加入不同微合金元素的DH36船板钢进行线能量为50 k J/cm和100 k J/cm的焊接热模拟试验,研究微...结合Ti、V、Nb元素对焊接热影响区微观组织的影响,添加不同微合金元素,进行实验室真空冶炼-轧制DH36高强船板钢。利用Gleeble3500试验机,针对加入不同微合金元素的DH36船板钢进行线能量为50 k J/cm和100 k J/cm的焊接热模拟试验,研究微合金元素V、Ti、Nb对焊接热影响区组织性能的影响。结果表明,在DH36焊接热影响区中,Ti生成了氧化物,该氧化物诱发了针状铁素体,钉扎了奥氏体晶界,而V、Nb并未生成夹杂物。展开更多
基金Supported by the National Natural Science Foundation of China(21076003,21272005)the Funding Project for the Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of the Beijing Municipality(PHR201107104,005000541211019/20,005000543111517)
文摘Ti/BMMs(Ti supported bimodal mesoporous silica) catalysts have been prepared via self-assembly route combined with ship-in-a-bottle method.The recovery and recycling performances of Ti/BMMs were investigated in the epoxidation of cyclohexene.In order to the evaluate the regeneration methods and to examine the deactivation behaviors,the deactivated Ti/BMMs catalysts were washed in chloroform or calcinated at 450 °C for 6 h and then activity of the recovery catalysts were examined.Meanwhile,the structure features and surface properties of the regenerated catalysts were characterized by X-ray diffraction,N_2-sorption analysis,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,thermogravimetric analysis,UV visible spectroscopy and X-ray photoelectron spectroscopy.The results showed that the typical bimodal mesoporous structure of recycled Ti/BMMs catalysts was still maintained,and the phenomenon of Ti leaching during the catalytic process and recovery was negligible.In particular,spectroscopic observations indicated that the effects of the regeneration methods on the tetrahedrally-coordinated Ti species and catalytic deactivation were remarkable.The main reasons were related to the polarities of used solvents during recovery tests,the environment medium of adsorbed water inside mesopore channels and the deposition of bulky molecules of by-products on the mesoporous surface.
文摘结合Ti、V、Nb元素对焊接热影响区微观组织的影响,添加不同微合金元素,进行实验室真空冶炼-轧制DH36高强船板钢。利用Gleeble3500试验机,针对加入不同微合金元素的DH36船板钢进行线能量为50 k J/cm和100 k J/cm的焊接热模拟试验,研究微合金元素V、Ti、Nb对焊接热影响区组织性能的影响。结果表明,在DH36焊接热影响区中,Ti生成了氧化物,该氧化物诱发了针状铁素体,钉扎了奥氏体晶界,而V、Nb并未生成夹杂物。
